This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

TIDA-050039: TIDA-050039 TPS61089 design adaptation for microbial fuel cells

Part Number: TIDA-050039
Other Parts Discussed in Thread: TPS61089, TPS61088

We are working to use the TIDA-050039 single solar cell energy harvesting design with microbial fuel cells which have a similar Maximum Power Point profile to single solar cells.  We want to adjust the Li-Ion design for 4.5-5.5V (4 x 1.2V cells) NiMH battery charging up to 2 watts (400-500 mA)  from fuel cell input at 0.45 volts. We would appreciate suggestions for adjusting TIDA-050039 components, particularly compensation, and advice on expected power conversion limits.

  • Hi Robert,

    Thank you for reaching out on E2E.

    The TI reference design TIDA-050039 application is quite similar to your application. Before talking about component adjustment, please note as the boost converter TPS61089 has a 2.7V UVLO limitation, only the battery voltage is higher than 2.7V, the circuit could start working. If you are charging a battery voltage less than 2.7V, the circuit cannot startup at all.

    1. As your design charging current is far higher than this reference design, I suggest you replace TPS61089 with TPS61088. TPS61088 has higher current capability, lower Rdson to achieve higher efficiency.

    2. In the original design, the boost converter maximum output voltage is limited to 4.2V. In order to adjust the maximum output voltage to 5.5V, change resistor R8 to 55koh,

    3. Adjust resistor R19 to 280kohm to set OVP voltage to ~5.7V.

    As for compensation, I cannot give a quick suggestion. It's always needed to tune the compensation based on real bench test.